Either the color of flowers or the color of vase can be changed.
Magician shows a white flower vase which both flowers and vase are white to the audience. Then he puts a red silk on the vase and when he takes the red silk from the vase, the color of vase and flowers have been changed to red! Instantly he puts a yellow silk on the vase and when he takes it from the vase, colors of vase and flower have been changed to yellow.
It is easily portable because the vase is easily separable from the bouquet.